Lewis Base Polymers for Modifying Sorption and Regeneration Abilities of Amine-Based Carbon Dioxide Capture Materials

In this work, we investigate the effects of modifiers on the carbon dioxide (CO2) capture/release abilities of silica-supported amine-based polymers. The primary aminebased polymers consisted of branched poly(ethylene amine) (PEI) and jeffamine T-403, having aliphatic and ether-based backbones, respectively. These polymers were dispersed on nanosilica, and their CO2 capture/release abilities were determined with and without the addition of the Lewis basic polymer modifiers, poly(vinyl acetate) (PVAc), poly(methyl methacrylate) (PMMA), and poly(ethylene glycol) (PEG). The greatest effect for increasing the CO2 capture capacity was observed for PEG additives while other modifiers lowered the capture capacity. However, PVAc and PMMA were found to significantly influence the kinetics of absorption and desorption. For absorption, modifiers improve mass transfer and offer better coverage of the silica surface so more amine groups are available at the surface of the sorbent for CO2 binding. Most markedly, while PEG improved desorption, PMMA and PVAc led to even faster desorption rates and higher regeneration abilities at 45 degrees C without the need for further heating. Thus, a combination of PEG and other Lewis base-containing modifiers have the potential to be used in concert to fine-tune the capacity, mass transfer, regeneration ability, and kinetics for amine-based CO2 sorbents.